Why 1 MB matters
Job portals, college applications and many online forms accept files only up to 1 MB, and some email systems and chat apps handle files under 1 MB more smoothly. Phone scanning apps often produce 3–20 MB files, which are far over that limit.
What happens when you compress
Each page is rebuilt as a compressed picture, and the tool searches for the best quality that keeps the whole PDF under 1 MB (1,024 KB). Progress is shown page by page, and the final size appears before download. If the PDF is already under 1 MB, it is returned unchanged. You can compress several PDFs at once; each one is made smaller than 1 MB separately.
How much fits in 1 MB
Documents of roughly 5 to 20 scanned pages usually stay clear and readable at 1 MB. Very long PDFs, or pages full of photographs, may need splitting first.
Common problems and how to fix them
The text cannot be selected after compressing: pages are saved as pictures to reach the size; run OCR PDF on the result if you need searchable text. A very long PDF is slow on a phone: compress on a computer or split the PDF first. The result is still over a stricter limit: use Compress PDF to 500KB or 200KB.
Good habits
Remove blank and unneeded pages before compressing, keep your original, and open the result once to make sure every page is complete.